Sound reproduction



May 23 1933- E. D. TILLYER SOUND REPRODUCTION Filed Feb. 27, 1931 patented May 23, 1.933

y UNITED STATES PATENT OFFICE RATION OF AMERICA, A CORPORATION 0F DELAWARE SOUND REIRODUCT'ION Application filed February 27, 1931. Serial No. 518,782.

rIhis invention relates to improvements in sound reproduction and more particularly to sound' reproduction by means of a photosensitive cell or the like.

The principal object of the invention is to provide improved means and processes of producing a light streak of required dimensions and proportion on a sound track film without exposed edges to collect dirt, dust, etc.

Another object of the invention is the provision of optical means and of optical processes o-f producing a light streak of required size a-nd properties on the sound track of a sound track film.

Another'object of the invention is the provision of an improved bar streak light filament and improved means for focussing the same at required size on the sound track of a sound track film. .Y .Another obj ect of the invention is the provision of improved means for optically projecting the image of a bar streak light filament on the sound track of a sound track film together with means for regulating the size of the said image on the film.

Another object of the invention is the provision of improved means for producing a light streak on the sound track of a sound track film which will not collect dust or dirt particles to reduce or destroy sound effects.

Another object of the invention is the provision of an improved light chamber, lamp or bulb for producing a light streak to be projected on the sound track of a sound track Another object of the invention is the provision of means for projecting the light streak on the'sound track of a sound track film that will change the size of the image of said streak in one meridian only.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing. It will be apparent that many changes in the details of construction and arrangement of parts and the steps of the process may be made without departing from the spirit of the invention as expressed inthe accompanying claims.. I therefore do not wish to be limited to the details so shown and described yas the preferred yforms only have been shown and described'byA way of illustration.

Referring to the drawing:

Fig. I is a diagrammatic top or plan view partially in section and showing one form of the invention;

Fig. II is a diagrammatic top or plan view partially in section showing a second form of the invention; v

Fig. III is a cross section of the lamp and light filament on line III-III of Figs. I and II;

Fig. IV is a partial perspective view showing the streak focussed on the sound track of a sound track film; A j

Fig. V is a partial diagrammatic .perspective view showing a cylinder lens and7 the relation ofthe axis of the cylinder to film strip; v I Fig. `VI is a partial longitudinal cross section through the lamp showinga light streak formed thereon;

Fig. VII is a side View of Fig. VI;

Fig. VIII is a view similar to Fig. VI but showing a transparent covering over the light streak; and y Fig. IX is a side view of'F ig. VIII.

In the reproduction of sound in the prior art by means of a photo-sensitive -cell the light streak that is focussed on the sound track of the film has been produced mechanically by means of a'plate having a slit or slot cut therethrough, or the edges of two plates separated by a space to produce the light slit. Dust, dirt and foreign particles collect on the edges of the slit and result in a false reproductionof the sound impulses. Prior to my invention it has been considered impracticable if not impossible to produce a streak light filament of proportions minute enough for the required purpose of streak projection. It has also been held that such a filament small enough for the purpose would be means of streak light reproduction that will 100 unstable, that is to say, it would break, and

overcome these difficulties and add advantages not hitherto obtained, particularly in the provision of an improved lamp, bulb or light chamber for producing the streak.

Referring to the drawing wherein similar characters designate similar parts through out I provide a light chamber member 1 which may be in the form of a glass incandescent electric light bulb, which may be evacuated or gas filled if desired. Within the light chamber I support a streak bar filament 2, supported by the support 3 and held in longitudinal tension by the spring l and wire 5 whereby it is held in aligned position and prevented from warping and twisting out of position. I preferably coat the transparent glass walls 6 of the bulb with an opaque covering 7 having an uncovered portion or opening at 8 through which the light may be emitted from the bulb. The clear portion or opening 8 is aligned with the bar filament 2. This coating may be of gold electrically deposited thereon in a vacuum or otherwise or other metals similarly coated thereon as Well as other opaque substances.

In Figs. VI, VII, VIII and IX I have shown a commercial electric lamp bulb with the filament 9 therein. The clear glass bulb is coated with the coating 7 as in Figs. I and II and a light streak slit 10 cut therethrough. In Figs. VIII and IX the slit 10 is covered with a transparent plate 11 for protection and to prevent collection of dirt, dust, etc. aligned with the opening in the coating of the bulb 8 or 10 as the case may be is the sound track film 12, having the usual feed openings 13, the picture track 14, and the sound track 15. The sound track 15 is aligned with the opening in the coating of the bulb. Between the bulb and the film I insert the lens system 16 which will focus the image of the bar filament 2 or the light streak 10 as the case may be on the sound track of the film. By the proper selection of the lens I can provide that the lens 16 will not only focus the image of the streak on the film but it may be made to change the size of the image as well, preferably to reduce it. In this way a bar filament 2 of substantial diameter may be used, say three thousandths of an inch. The streak may be reduced on the film as desired, say to one thousandth of an inch.

'Ihe light rays pass through the lm 12 into the photo-sensitive cell 17, then to the amplifier 18 and then to the loud speaker 19 in the usual prior art way.

In the modification shown in Fig. II a cylinder lens 20 with its axis substantially normal to the length of the film and substantially parallel with the bar filament 2 or streak 10 as the case maybe is inserted between the lens system 16 and the bulb. It is clear that this lens will refract the image of the bar or streak only in the direction of the thickness of said bar or streak but not in the direction of its length. The image refracted by the cylinder lens is focussed on the film as before and the other arrangements are the same.

In Fig. IV the numeral 21 indicates the image of the bar or streak on the sound track of the film.

The operation is as follows: In Fig. I the image of the bar filament 2 is reduced in size and focussed on the sound track ofthe lm by the'lens system 16.A If the streak 10 form of bulb is used the image of this streak is similarly focussed on the film by the lens system 16, either reduced or not as depends on the width of the streak 10. Y

If the device of II is used the width of the bar or streak is refracted by the cylinder lens but not the length. This allows a reduction in the width of the streak without affecting the length. The operation of the remainder of Fig. II is the same as in Fig. I. It is clear that the lenses 16 may be of any desired power either plus or minus so that the image may be changed in size and focussed on the film in any desired ratio to the object.

The coating 7 may be put either on the outside or the inside ofthe lamp 1. If on the outside it is more readily maintained and repaired.

It is also clear that with' this invention there are no edges, ledges or shoulders to collect dirt and dust to interfere with the sound reproduction as in prior art devices and that in addition I have provided simple and eiiicient means for regulating the width of the streak on the film and the provision of an improved light chamber, bulb or lampv for producing the streak.

Having described my invention I claim:

1. In a device of the character described, a light producing lamp, a streak bar filament in the lamp, said streak bar filament being supported adjacent one end by a relativelyrigid support and adjacent its opposite end by a resilient support adapted to prevent distortion of the filament during its use, said resilient support being mounted in aligned relation with the longitudinal axis of the bar filament to prevent lateral displacement of said resilient member and filament, an opaque covering on the lamp having an opening therein adjae cent the bar filament, the said relatively rigid support of the bar filament being such as to hold the said filament in aligned relation with the opening and against the pulling ac-y tion of the resilient support adjacentits opposite end, and a sound track film in aligned relation with the openingadapted to receive light emitted by said opening.

2. In a device of the character described, a lamp bulb, a streak bar filament in the bulb, said streak bar filament being supported adjacent one end by a relatively rigid support and adjacent its opposite end by a resilient support adapted 'to prevent distortion ofthe filament during its use, an opaque covering on the bulb having an opening therein, the said relatively rigid support of the bar filament being such as to hold the said filament in aligned relation with the opening and against the pulling action of the resilient support, a transparent covering over the opening in the opaque coating acting as a seal for sealing the said portion having the opening therein between said transparent covering and the Wall of the bulb, and a sound track film in aligned relation with the opening adapted to receive light emitted from said opening.

EDGAR D. TILLYER. 

